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Re: S-LSA Aircraft Certification Requirements

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  • Dan Grunloh
    ... and panel ... Absolutely,... as most any triker will agree. But here is an interesting question. One would think that a weight shift LSA used to take the
    Message 1 of 8 , Aug 1, 2006
      --- In Sport_Aircraft@yahoogroups.com, "Jim Bair" <jimbair@...> wrote:
      >
      > Fixed wing, yes. Trikes, no. A/S on a trike is a waste of money
      and panel
      > space, in my opinion.
      > Jim


      Absolutely,... as most any triker will agree.

      But here is an interesting question. One would
      think that a weight shift LSA used to take the
      practical would require an ASI since there is
      a requirement for airspeed control in some of the
      ground reference manuvers (+- 10 knots).

      I asked a weight shift DPE at Oshkosh about it
      and he admitted he didn't have one on the trike
      he uses for exams.

      I guess it's up to the examinar. A good examinar
      can probably tell very quickly (without an ASI) if
      the applicant has exceed those speed limits in a
      trike. I mounted a Hall just for fun and did some
      steep turns. It ain't hard to stay within 10 knots
      in a turn unless you are all over the sky.

      Another caveat......

      In a SLSA, how is the manufacturer to be assured that
      the pilot will not inadvertantly exceed Va or VNE in
      his machine without an ASI. How will he know that
      he has not exceeded the operating limitions as required
      by regulations? I think if I was a LSA manufacturer I
      would put an ASI on my trike products so as to prevent
      lawsuits from customers who DID inadvertantly exceed the
      operating limits I set for the machine.

      --Dan Grunloh
    • abidfarooqui2003
      Hi Dan, ASTM standards for WSC require an ASI in a S-LSA trike. Also, you are right that in certain trikes but not most, its quite possible to easily exceed
      Message 2 of 8 , Aug 1, 2006
        Hi Dan,
        ASTM standards for WSC require an ASI in a S-LSA trike.
        Also, you are right that in certain trikes but not most, its quite
        possible to easily exceed VNe and Va. In Delta jet when equipped with
        the 12 meter wing, its quite possible to exceed its 99 MPH VNe by a
        noticeable amount (117 to 115). Its also very possible to go past its
        Va of 90 MPH. Hence an ASI in it makes very good sense.
        But the point is moot because all new ASTM compliant trikes will have
        an ASI to meet the standard anyway.
        Sincerely,
        Abid

        --- In Sport_Aircraft@yahoogroups.com, "Dan Grunloh" <dgrunloh@...> wrote:
        >
        > --- In Sport_Aircraft@yahoogroups.com, "Jim Bair" <jimbair@> wrote:
        > >
        > > Fixed wing, yes. Trikes, no. A/S on a trike is a waste of money
        > and panel
        > > space, in my opinion.
        > > Jim
        >
        >
        > Absolutely,... as most any triker will agree.
        >
        > But here is an interesting question. One would
        > think that a weight shift LSA used to take the
        > practical would require an ASI since there is
        > a requirement for airspeed control in some of the
        > ground reference manuvers (+- 10 knots).
        >
        > I asked a weight shift DPE at Oshkosh about it
        > and he admitted he didn't have one on the trike
        > he uses for exams.
        >
        > I guess it's up to the examinar. A good examinar
        > can probably tell very quickly (without an ASI) if
        > the applicant has exceed those speed limits in a
        > trike. I mounted a Hall just for fun and did some
        > steep turns. It ain't hard to stay within 10 knots
        > in a turn unless you are all over the sky.
        >
        > Another caveat......
        >
        > In a SLSA, how is the manufacturer to be assured that
        > the pilot will not inadvertantly exceed Va or VNE in
        > his machine without an ASI. How will he know that
        > he has not exceeded the operating limitions as required
        > by regulations? I think if I was a LSA manufacturer I
        > would put an ASI on my trike products so as to prevent
        > lawsuits from customers who DID inadvertantly exceed the
        > operating limits I set for the machine.
        >
        > --Dan Grunloh
        >
      • Jim Bair
        ... I do find it nice, but not necessary, to have an A/S indicator when I m instructing so I can see precisely what the student is doing with the bar very
        Message 3 of 8 , Aug 2, 2006
          > > Fixed wing, yes. Trikes, no. A/S on a trike is a waste of money
          > and panel
          > > space, in my opinion.
          > > Jim
          >
          >
          > Absolutely,... as most any triker will agree.
          >
          > But here is an interesting question. One would
          > think that a weight shift LSA used to take the
          > practical would require an ASI since there is
          > a requirement for airspeed control in some of the
          > ground reference manuvers (+- 10 knots).
          >
          > I asked a weight shift DPE at Oshkosh about it
          > and he admitted he didn't have one on the trike
          > he uses for exams.
          >
          > I guess it's up to the examinar. A good examinar
          > can probably tell very quickly (without an ASI) if
          > the applicant has exceed those speed limits in a
          > trike.

          I do find it nice, but not necessary, to have an A/S indicator when I'm
          instructing so I can see precisely what the student is doing with the bar
          very easily. On a higher performance trike, it doesn't take much pull in or
          push out to change the A/S, and some students can mask their light grip
          quite easily. :)

          The steep turn is where the "coordinated" use of pitch becomes noticeable
          very quickly. I can tell very quickly whether a student has that concept
          just by watching them perform that maneuver, and yes, the PTS standard is
          loose enough in terms of percentage (a trike applicant flying a 50 kt trike
          is allowed 10 kts or 20% of cruise speed in error. A 100 kt cruise
          applicant is allowed 10 kts or 10% error. In other words, a higher airspeed
          flyer is held to a higher standard. 20% is a lot of slop.) that an
          applicant could do a steep turn poorly on a low performance trike and still
          not exceed the 10 kt standard, but if he doesn't push out a bit in steep
          turns then he isn't displaying much in the way of knowledge of aerodynamics
          of how to maintain a constant airspeed in a turn. The +- 10 kt thing is to
          allow for human error, not a standard to shoot for on purpose.

          Jim
          www.SportAviationUnlimited.com
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